Couple things to check. First, keep in mind this is a "chipper" not a "chipper-shredder". It's really meant for woody material that creates chips. For leafy/twiggy material you have to limit and alternate what you feed because the unit does not have a shredding capability. I always alternate beefier woody material after feeding lots of leafy/twiggy material through, which helps to blow out the chute and keep it clean. So periodically send through something woodier like a beefy limb, to make actual chips and blow any small stuff out. If you only deal with small leafy/twiggy material, then you really need to find a chipper-shredder instead. Second, check all of the knife-to-anvil clearances and make sure the knives are sharp and in good condition. When feeding a limb through, the chipper should peel off nice clean chips and have very good flow through the chute. If that is not happening, it will hurt flow and that can make backups more likely. Finally, check the "twig breaker" which is on the inside of the housing below the hinge (where the housing swings open). There are 1-2 (depending on year) fins that poke into the housing and pair up with slots on the flywheel paddles. This is meant to snap any twigs or small material that makes it through the knives without getting chipped. If the fins are broken/gone, then you will be sending large twigs into the chute and it will lead to plugs. Good luck! I've had this unit for about 10 years and it's been very reliable and productive. In that whole time, I think I only had it plug up 2-3 times, mainly when sending wet leafy material through. I don't think it has ever plugged on our yellow pine here, which is the primary use. The yellow pine tends to have fairly woody limbs that creates good chips, so the needles aren't a problem.

32HP total, 25HP at the PTO.

I had bought it for a previous B-series Kubota in about 2012 if I recall right. Bearings have been fine so far, but that reminds me it's probably time to get out the grease gun and hit everything. The PTO shaft is at about 15-20 degree angle when the chipper is down on the ground. PTO shafts will have a specific angle limit depending on the joint type/design, and it's worth checking to see what the shaft is spec'd for. I believe basic shafts can run at up to 25-30 degrees angles. If the angle is too steep, you can rest the chipper on some timbers or bolt some lumber to the skids to raise it up and reduce the shaft angle.

I just set it to output 540 RPM at the PTO, which is the standard RPM most implements are designed for. There is a little mark on the tachometer to let me know where to set the engine speed to correspond to 540 RPM at the PTO. Most tractors will have a mark on the tach or tell you what engine speed results in 540 RPM at the PTO.

Knives can be flipped to get a fresh edge. I am still using the first edge and they feel sharp to the touch but will need to be flipped at some point. Once both edges are dull, they can be re-honed. Most people send them out to a pro for this but I am told it's possible to do at home using a true surface and various grits of wet-sand paper.